<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div id="app">
        <p v-for="(item,index) in arr" :key="index">
            <span>下标是{{index}}，数组项是{{item}}</span>
        </p>
        <p v-for="(a,b,index) in brr" :key="index">
            <span>键是{{b}}，值是{{a}}</span>
        </p>
    </div>
    <script src="https://cdn.jsdelivr.net/npm/vue@2"></script>
    <script>
        var app = new Vue({
            el: '#app',
            data: {
                arr: [12, 34, 56, 78, 90],
                brr: {
                    'a': 12,
                    'b': 34
                }
            }
        })
    </script>
</body>

</html>